The "do what it takes to get elected" theme, taken to its logical conclusion in a two party system, would yield two indistinguishable candidates from the "left" and "right", competing over a tenuous grasp of the center. Or, so goes the usual logic from American third party wannabes.

What's actually going on, starting with Karl Rove's work for George W. Bush, is a realization that election turnouts are so amazingly low that "energizing the base" with a more extreme candidate can actually work. We see that, in spades, with the various local victories of "Tea Party" Republican candidates in the 2010 election, who are very much farther to the right than traditional Republicans. (Notable case in point: even Utah Republican Orin Hatch is taking fire from his right flank.)

Obama's recent policies and speeches, viewed through a purely political lens, seems engineered to grab onto something resembling the political center, around the assumption that the Republicans are certainly not going to try to attack him from the left, nor will other American left-leaning organizations (Green Party, etc.) mount a credible opposition from the left.

Of course, the net effect is that the U.S. now has two center-right parties with no meaningful representation from what might traditionally be considered the political left.

If you believe Larry Lessig, all of these imbalances boil down to dysfunctions in how political campaigns are financed and I'm tempted to agree with him. I'd also point the finger at the broad dysfunction of our news organizations to report, well, actual news. Of course, who can resist the latest Charlie Sheen antics.

The "winner takes all" mechanics of our voting systems are also a reasonable suspect. There's no lack of alternative voting systems used elsewhere in the world, but not in the U.S. If there were some credible way to vote for a third party candidate without "spoiling" the "real" election between the "big" candidates (yeah, lots of quotation marks), then third parties could play a legitimate role in our elections that's denied to them today.